The present invention relates to an acoustic attenuating liner. More particularly, the invention relates to a segmented resistance acoustic attenuating liner.
Typical jet engine acoustic liners are designed with a uniform acoustic impedance to attenuate a specific acoustic mode of the engine noise signature. Segmented liners have been used to attenuate several modes and noise levels at several frequencies by having separate resistance and core depth values over the liner area. While offering significant advantages, these liners are more complex to manufacture and have reduced acoustically treated areas due to interfacing at the segment boundaries. The reduced acoustic areas result from splicing the facesheet wire mesh, splicing the honeycomb core and requirements for added parts to mechanically fasten the segments.
The principal object of the invention is to provide an acoustic attenuating liner of simple structure which functions efficiently, effectively and reliably to reduce the noise of a jet engine.
An object of the invention is to provide an acoustic attenuating liner which is lightweight, durable and corrosion-resistant.
Another object of the invention is to provide an acoustic attenuating liner suitable for use with high bypass aircraft jet engines.
Still another object of the invention is to provide an acoustic attenuating liner having a single perforated sheet used for all segments of different resistance.
Yet another object of the invention is to provide an acoustic attenuating liner having a single perforated sheet used for all segments of different resistance, the resistance of which is dependent on a wire mesh thereof only.
Another object of the invention is to provide an acoustic attenuating liner having no splices between segments of different resistance and providing improved engine noise attenuation.
Still another object of the invention is to provide an acoustic attenuating liner which is inexpensive in manufacture due to a reduced number of component parts, reduced parts handling and reduced weight.
Yet another object of the invention is to provide an acoustic attenuating liner of simple structure which is inexpensive in manufacture and functions efficiently, effectively and reliably to attenuate the noise of a jet engine.